Crimguy

Hi all - I am the proud owner of a 2005 Z Convertible, which I brought from my brother. I need a decent mechanic in Phoenix, AZ to help with some overheating issues. My mechanic is apparently lazy, not very thorough, or a combination of that and just not bright ;-D

Radiator is 18 months old. Overheats when at a standstill. Fan seems to be working. I bled the radiator and refilled with 50/50 and no help. The mechanic diagnosed it as a faulty radiator cap and charged me $10 which is nice I guess but it didn't help.

Other problems have cropped up in the past month as well - passenger door handle stopped working and right rear tire has mysteriously started wearing prematurely at the outer edge.

Thanks for any recommendations. Car was previously serviced at Precision Z in Canoga Park, which I understand is a top flight outfit.

i8acobra

iTrader: (6)

I'm not in Phoenix any more, or I'd look at it. Moved back to Vegas. The overheating is likely the thermostat. It's a VERY common issue on the VQ motors. Door handle could be the rod retainer broke and the rod came out of the handle. Eay fix, but the door panel has to come off. Tire wear is likely alignment. Replace the rear tires as a set, then get it aligned.

icer5160

iTrader: (4)

Hi Crim,

As cobra stated you could have a bad thermostat, but if the radiator was recently replaced, it's also possible you have major air pockets still trapped in the coolant loop. A quick check would be to listen carefully any odd noises coming from the dash upon a cold start in the morning. If you hear some fluid bubbling noises, then you still have air trapped in the coolant loop. The dash noise check indicates air bubbles trapped in the heater core. Air bubbles love to settle there.

May I ask who replaced the radiator and burped the system? Was the coolant bleeder valve used when filling up the system? A lot of mechanics not familiar with Z33s forget about this crucial part of the procedure when refilling the system. It's not impossible to get the air out using a spill free funnel, but it will take multiple hot/cold cycles and revving the engine to purge all the air out.

I suspect trapped air is the problem since you mentioned the overheat scenario only occurs while at a stand still and the fans are working. A sticking or failing thermostat would typically produce a overheat scenario both while driving and at a stand still. I also recommend a thorough check around coolant hoses. Look for any signs of a slow leak, also monitor your coolant overflow level. When cold, it should be at the MAX line. Once per week I would check the level before the day's 1st start, if you find that the level is slowly dropping, then you have a slow leak issue somewhere.

I agree with cobra's other assessments regarding the door handle and tire wear.
Cheers!
-Icer

CRBWS6

I concur with icer5160. Of all the cars I have owned, the Z was by for the most difficult to do a coolant flush on. Air gets trapped and prevents the t-stat from opening. I am very **** about flushing coolant on a regular basis so I noted a few tips:

1. Lift front end (ramps or jack stands)
2. Use a coolant funnel (the kind that comes with a set of radiator cap adapters for a tight fit).
3. Run the engine 3-4 short iterations (5-7 min each) and rev repeatedly to 3k. The reason for the short runs is in case there is lots of air and you don't want to overheat it.
4. Leave funnel in place, let car cool down and top off coolant after each iteration.
5. Remove funnel and close radiator cap. Squeeze upper hose, and while still squeezing, partially open the plastic Phillips head bleeder screw located on the heater hose at the back/driver side of the engine compartment.
6. You will know the air is out when the heater blows hot air at idle (not just when revving engine) and lower hose only slightly less hot than upper.

As for mechanics, I did one time use Pitstop Performance which on 7th Ave in central Phx and they definitely know Z cars very well. Vitaly was the owner.

bealljk

iTrader: (13)

There comes a point where you need to get air out of the system more than you need to get coolant into the system.

If you still cant get it, use the bleeder valve in the back to purge air out and/or disconnect one of the small coolant hoses on the thermostat and purge air from this point. You can also try to fill from these points as well (easier said than done).

Not recommended unless you are versed at ‘cars’ but you can get the car ‘warm’ to ‘hot’ and ever-so-carefully open the radiator cap a tiny bit which will push air out. You should have full PPE (leather gloves, long sleeves, eye/face protection, etc) on while doing this. Do not try this if you are new to automotive repair.